• Title/Summary/Keyword: Mu-Wi

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A MU-MIMO User Scheduling Mechanism based on Active CSI Exchange (능동적 CSI 교환을 기반으로 한 MU-MIMO 유저 스케줄링 기법)

  • Lee, Kyu-Haeng;Kim, Chong-Kwon
    • Journal of KIISE:Information Networking
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    • v.41 no.4
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    • pp.192-201
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    • 2014

  • User scheduling boosts the Multi-User Multi-Input Multi-Output (MU-MIMO) gain by selecting an optimal set of users to increase the 802.11 Wi-Fi system capacities. Many kinds of user scheduling algorithms, however, fail to realize the advantages of MU-MIMO due to formidable Channel State Information (CSI) overhead. In this paper, we propose a user scheduling method considering such CSI exchange overhead and its MAC protocol, called ACE (Active CSI Exchange based User Scheduling for MU-MIMO Transmission). Unlike most proposals, where user scheduling is performed after an Access Point (AP) receives CSI from all users, ACE determines the best user set during the CSI exchange phase. In particular, the AP broadcasts a channel hint about previously scheduled users, and the remaining users actively send CSI reports according to their Effective Channel Gains (ECGs) calculated from the hint. Through trace-driven MATLAB simulations, we prove that the proposed scheme improves the throughput gain significantly.

  • KSCI

A Study on Lawful Interception Architecture for IEEE 802.16e Wireless/Mobile Networks (IEEE 802.16e/WiBro 휴대 인터넷망을 위한 합법적 감청 아키텍처에 관한 연구)

  • Myoung-rak Lee;Dong-hyun Lee;Seung-bin Kim;Hoh Peter In
    • Proceedings of the Korea Information Processing Society Conference
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    • 2008.11a
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    • pp.1485-1488
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    • 2008

  • Lawful Interception (LI) 이란 합법적인 형태의 도청을 말하며, 전통적인 Wired tapping 뿐만 아니라, 최근의 복잡해진 인터넷 및 통신환경의 여러 형태의 데이터들에 대한 감청이 포함 될 수 있다. 미국과 유럽 중심으로 개발 된 감청 표준들은 3 세대 통신망 위주의 감청을 위한 표준들이 대부분이며, 802.16e 기술중의 하나인 모바일 WiMax 를 위한 합법적 감청 표준 개발은 진행 중에 있는 실정이다. 특히, Wibro 와 같이 모바일 유닛(MU)이 Radio Access Contro (RAS)와 Access Control Router (ACR)를 자유롭게 이동하는 상황에서 패킷들에 대한 지속적인 추적은 합법적 감청 분야의 중요한 이슈 중의 하나이다. 따라서, 본 논문에서는 국내의 802.16e/WiBro 네트워크 사용자의 증가 및 그에 따른 보안위협 발생의 가능성 증가에 따라 합법적인 감청을 위한 효과적인 아키텍처를 제안하고자 한다. 본 논문에서 제안하는 아키텍처는 802.16e/WiBro 망내의 합법적 감청을 위하여 네트워크상에서의 효과적인 감청 관련 정보 교환을 위한 기본적인 메커니즘을 포함하고 있다.

  • https://doi.org/10.3745/PKIPS.y2008m011a.1485 인용 PDF

The infection of Myxobolus sp. in wild mullet, Mugil cephalus (자연산 숭어(Mugil cephalus)의 Myxobolus sp. 감염증)

  • Kim, Wi-Sik;Lee, Mu-Geun;Park, Gyeong-Hui;Jeong, Seong-Ju;O, Myeong-Ju
    • Journal of fish pathology
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    • v.16 no.1
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    • pp.31-38
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    • 2003

  • The mortality of wild mullet, Mugil cephalus was detected in Kwang- Yang bay on February, 2002. The mullet were infected with Myxobolus sp., the cysts of Myxobolus sp. were found in the mesentery, liver, gill and pharyngeal pocket. The histological findings suggested a systemic infection by the Myxobolus sp.. The spores were measured 10-12 (10.9)${\mu}m$ in length, 9-10 (9.4) ${\mu}m$ in width, 6.4-7.2 (6.8) ${\mu}m$ in thickness, with polar capsules of 4-5.2 (4.4) ${\mu}m$ in length and 2.5-3.3 (2.9) ${\mu}m$ in width.

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Particulate Matter 10 from Asian Dust Storms Induces the Expression of Reactive Oxygen Species, NF-κ, TGF-β and Fibronectin in WI-26 VA4 Epithelial Cells (황사의 PM10이 WI-26 VA4 Cells에서 Reactive Oxygen Species, NFκB, TGF-β, Fibronectin의 발현에 미치는 영향)

  • Park, Kyeong Seon;Kim, Yu Jin;Yoon, Jin Young;Kyung, Sun Young;An, Chang Hyeok;Lee, Sang Pyo;Park, Jeong Woong;Jeong, Sung Hwan
    • Tuberculosis and Respiratory Diseases
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    • v.65 no.6
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    • pp.504-511
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    • 2008

  • Background: Particulate matter may be toxic to human tissue. Ambient air particulate matter ${\leq}10{\mu}m$ in aerodynamic size ($PM_{10}$), which changes under different environmental conditions, is a complex mixture of organic and inorganic compounds. The Asian dust event caused by meteorological phenomena can also spread unique particulate matter in affected areas. We evaluated production of ROS, $TGF-{\beta}$, fibronectin, and $NF{\kappa}B$ by exposing normal epithelial cells to Asian dust particulate matter. Methods: Bronchial epithelial cells were exposed to 0, 50, ${\leq}100{\mu}g/ml$ of a suspension of $PM_{10}$ for 24 h. ROS were detected by measurement of DCF release from DCF-DA by FACScan. $TGF-{\beta}$, fibronectin, and $NF{\kappa}B$ were detected by western blotting. Results: $PM_{10}$ exposure increased the expression of $TGF-{\beta}$, fibronectin, and $NF{\kappa}B$. ROS production and $TGF-{\beta}$ levels were significantly higher with 50 or ${\leq}100{\mu}g/ml$ $PM_{10}$. Fibronectin and $NF{\kappa}B$ production were significantly higher after ${\leq}100{\mu}g/ml$ of $PM_{10}$. Conclusion: $PM_{10}$ from Asian dust particles might have fibrotic potential in bronchial epithelial cells via ROS induction after $PM_{10}$ exposure.

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